British man arrested over mass stabbing attack on a train in England. Here’s what we know

Leon Neal/Getty Images via CNN Newsource

(CNN) — Britain was shocked by a mass stabbing attack on a train Saturday evening that targeted passengers as they traveled through central England on their way to London, in an incident Prime Minister Keir Starmer has described as “deeply concerning.”

The attack left nine people in need of treatment for life-threatening injuries, one of whom was still fighting for his life in hospital on Sunday evening, after what the British Transport Police (BTP) declared a “major incident.”

Though two suspected attackers were initially detained within minutes of police receiving their first emergency call, BTP said on Sunday evening that only one person is now being treated as a suspect.

A 32-year-old British man remains in police custody after being arre